Fire tube heat flow regulators



Oct. 6, 1964 s, EVANS 3,151,582

FIRE TUBE HEAT FLOW REGULATORS Filed Nov. 20, 1962 FiGl gALPH s. EVAN 5JM M United States Patent 3,151,582 TUBE T-TEAT FLSW Ralph S. Evans,4711 f ll J. 175th St, Fla. Fiied Nov. 2% 1962, Ser. No. 23%,932 7Claims. (51. 119-97} This invention relates to boiler construction andis more particularly directed to fire tube heat flow regulators forboilers.

A principal object of the present invention is to provide heat flowregualtors for fire tube boilers that increase the efficiency of theboilers when firing at less than its full capacity.

Another object of the present invention is to provide heat flowregulators for fire tube boilers that prevent the hot combustion gasesfrom flowing through the upper banks of fire tubes but compels the gasesto be diverted so as to pass through all of the fire tubes.

A further object of the present invention is to provide heat flowregulators for each row or group of rows of tubes of a fire tube boilerwherein the regulators are provided with valve plates of variousthicknesses, the plates decreasing in weight in the direction of thelower group of valve plates to direct the flow of gases through thelower fire tubes at low capacity operation.

A further object of the present invention is to provide heat flowregulators for each tube of a fire tube boiler, which regulators aresimple in construction, inexpensive in cost, readily positioned in thefire tubes and most effective to raise the eificiency of the boiler whenfiring at low capacity.

A still further object of the present invention is to provide a firetube boiler with a plurality of heat fiow regulators that permit thepurging and cleaning of the fire tubes and permit some flow ofcombustion gases therethrough even when the boiler is firing at itslowest capacity.

With these and other objects in view, the invention will be bestunderstood from a consideration of the following detailed descriptiontaken in connection with the accompanying drawing forming a part of thisspecification, with the understanding, however, that the invention isnot confined to any strict conformity with the showing of the drawingbut may be changed or modified so long as such changes or modificationsmark no material departure from the salient features of the invention asexpressed in the appended claims.

In the drawing:

FIGURE 1 is a cross sectional view of a fire tube boiler embodying myinvention.

FIGURE 2 is a detailed fragmentary sectional view of my heat flowregulators shown in position on a fire tube.

FIGURE 3 is a front elevational view thereof.

FIGURE 4 is an exploded perspective view of the fire tube regulator.

FIGURE 5 is a fragmentary side elevational view of the valve plates 23showing the variation in thicknesses of the various heat flowregulators.

Referring to the drawing wherein like numerals are used to designatesimilar parts throughout the several views, the number It) refers to afire tube boiler of conventional construction and to which have beenadded my heat fiow regulators 11.

The fire tube boiler 16 consists of the usual outer walls to form acombustion chamber 12, passageway for combustion gases 13, heat exchangechamber 14 and fiue or stack 15 for the discharge of the combustiongases.

Mounted on a front wall 16 of the boiler 19 is a burner 37 which directsthe air and oil or gas to mix and become ignited in the combustionchamber 12. The hot c0m-.

bustion gases will fiow along the passageway 13 and into some of themany fire tubes 17 which extend between front and rear walls 18 and 19respectively, which with 3,151,582 Patented Got. 6, 1964 top and bottomwalls 30 and 31 form the water chamber of the boiler 10. The fire tubes17 are arranged in a vertical bank of horizontal rows of fire tubes 17so that a maximum rate of heat exchange between the hot combustion gasesand the water in the Water chamber is effected.

The boilers it) are constructed to provide maximum eficiency at a highrate of heat exchange or at high fire as it is known in the art. All ofthe fire tubes 17 receive approximately the same amount of combustiongases and therefore transmit to the water approximately the same amountof heat or B.t.u.s. However, when the boiler is operating at below highfire, the draft at the burner is reduced and the total amount ofcombustion gases is now less than at high fire. The passage 13 will nowhave a smaller volume of combustion gases passing therethrough than whenthe boiler It was firing at high fire. However, the hot combustion gaseswill rise to the upper portion of the passage 13 thereby causing agreater proportion of the combustion gases to flow through the upperhorizontal rows of fire tubes 17 while the lower rows of fire tubes 17will receive a very small proportion of the total combustion gases. Thiscondition, of course, reduces the efiiciency of the boiler inasmuch asthe combustion gases passing through the upper fire tubes 17 will enterthe stack 15 at a higher temperature than the combustion gases passingthrough the lower fire tubes 17.

The function of the instant devices or heat fiow regulators 11 is toprovide for the passing of approximately equal flows or volumes ofcombustion gases through all of the fire tubes 17 at all conditions offiring from high fire to low fire. The heat flow regulators 11 which aremounted at the discharge end of each of the fire tubes 17 consist of atubular body portion 29 of the same diameter as that of the fire tubes17. A plurahty of symmetrically disposed seating prongs 21 are welded orotherwise secured to the inner surface of the tubular body portion 2%and extending beyond the inner edge thereof. Since the tubular bodyportion is of the same diameter as the fire tubes 17, the prongs 21 willfit snugly in the fire tubes 17 to retain the heat flow regulators 11securely in position on the discharge end of the fire tubes 17 as bestshown by FIGURE 2.

At the upper forward edge of the tubular body portion 2% is a hinge lug22 on which a flap valve 23 is pivotally mounted. The flap valve 23 isprovided with a pair of binge lugs 24- which lie on either side of thehinge lug 22 and in ali nment therewith to receive the hinge pin 25 forpivotal movement of the fiap valve 23. A cotter pin 27 secures the pivotpin 25 on the lugs 22 and 24. The fiap valve 23 is a gravity actuatedvalve normally in a closed position as shown by FIGURE 2. However, thevalve plate 23 is oval at its lower portion rather than circular as isits upper portion thereby providing an opening 26 for the minimal fiowof combustion gases when the valve 23 is in its closed position. Theopening 26 which is at the lower portion of the fire tubes 17 permits aflow of gases at all time, the opening enlarging in proportion to thevolume of flow of combustion gases.

It is to be noted that the fiap valves 23 are all of the same shape andconfiguration except however, the thickness of the plates 23. As bestshown by FIGURE 5, the valve plate 23 designated by the letter A is thethickest and heaviest plate valve mounted on the top row of the firetubes 17. The valve plates B, C, D and E which are progressively thinnerand lighter are mounted on the consecutively lower rows of the firetubes 17.

The opening at; being positioned at the lower portion of the fire tubes17 permits blowing combustion products, grime, etc. out of the firetubes 17 to clean same. Also, before firing the boiler 10 and beforeturning on the fuel a gas fired boiler, the burner 37 is actuated toa,151,esa

combustion chamber 12 and blow air only through the .fire tubes 17 topurge the area of any dangerous gases will be fiowing through all of thefire tubes and the boiler will be firing to provide a maximum heatexchange. As

the draft is decreased, the volurne flow of combustion gases willdecrease. ventional fire tube boiler, the hot combustion gases will 7rise in the chamber 13 and fiow only through the upper Y fire tubes 17while little or none of the combustion gases will flow through the lowerfire tubes 17. This condition Under these conditions in the conclosedposition said valve plate permits a limited flow of combustion gases.

3. In a fire tube boiler having a plurality of fire tubes,

each of said fire tubes having an inlet and an outlet, a plurality offire tube heat flow regulators each comprising a cylindrical body memberhaving substantially the same diameter as said fire tubes, removablemeans securing said body members to said outlets of said fire tubes, aplurality of'valve plates, pivot means mounted on an upper portion ofeach of said valve' plates and said body members pivotally mounting eachof said valve plates to said body members and normally retaining saidvalve plates in a closed position, said valve plates swinging reducesthe efficiency of the boiler It? since only a p ortion of the fire'tubes17 are being utilized and the total amount of heat transmitted to thewater will be less than if all the fire tubes were being used. In theboiler 19, the combustion gases will not be flowing in sufiicient volumeto maintain the heavier valve plates 23 of the upper fire tubes 17 in acompletely open condition but will be only partially open therebycausing the combustion gases to fiow through the lower fire tubes 17that have the lighter fiap valve plates 23. As the draft is decreasedfurther, the upper and heavier flap valves 23 will come to a closedcondition allowing only a minimal flow of combustion gases therethrough.The lower fiap valves 23 will be open to a greater extent in thedirection of the bottom fire tubes 17. This compels the combustion gasesthat tend to risein the boiler 19 to be directed so as to fiow throughall of the fire tubes and thereby maintain the heat exchange at itshighest efficiency at all stages of draft, from a maximum draft when allthe. flap valves 23 are open to a minimum draft when all of the flapvalves 23 are closed.

My heat fiow regulators 23 are especially useful in those boilers whichhave been converted from oil burning boilers to gas burning boilers, thereason being that the combustion chamber for oil burning boilers islarger than that of the gas burning boiler. When the converted boiler,is being used at full capacity its combustion chamher is still too largefor efficient; heat exchange. However, with the use of applicants heatflow regulators 23, the combustion gases will be evenly'distributedamong all the fire tubes as in the boiler 16 when used at below highfire. a I e What I claim as new and desire to secure by Letters Patentof the United States is:

1. In'afire tube boiler having a plurality of fire tubes, each of saidfire tubes having an inlet'and an outlet, a fire tubeheat fiow regulatorcomprising a body member, means securing said body'rnembe'r to saidoutlet of said fire tube, a valve plate, pivot means yieldingly mountingsaid valve plate on said body member in a normally closed position, saidvalve plate swinging in a direction away from said fire tube to an openposition upon suffi cient pressure being exertediby combustion gases andbeing smaller than said fire tube whereby an opening is formed with saidvalve plate in said closed position to permit a restricted flow ofcombustion gases through said firetube. a a

2. la a fire tube boiler having a plurality of fire tubes,

each "of said fire tubes having an inlet and an outlet, a

. fire tube heat flow regulator comprising a body member, removablemeans securing said body member to said outlet of said fire tube, avalve plate, pivot means mounted on an upper portion of saidi bodymemberand said valve plate pivotally mounting said valvefplate .to'saidbody member and yieldingly -15etaining said valvelplate against saidbody member in a closed position, said valve plate being swung to itsopen position by sufiicient pressure exerted by cornbustiongases in saidfire tube and beingslotted at itslower portion whereby its normally toan open position upon suificient pressure being exerted by combustiongases flowing through said fire tubes and each valve plate having alower portion terminating in spaced relation to the lower edge of saidbody members forming an opening for the flow of restricted combustiongases therethrough when said valve plates are in a closed position uponthe pressure of combustion gases being insufiicient to open said valveplates.

4. In a fire tube boiler having a plurality of horizontally disposedfire tubes mounted in a vertical tier, each of said fire tubes having aninlet and an outlet, a plurality of fire tube heat fiow regulators eachcomprising a cylinvalve plates to said body members and normallyretaining said valve plates in a closed position, said valve platesswinging to an open position upon sufficient pressure being exerted bycombustion gases flowing through said fire tubes and each of said fireplates having an upper portion engaging said body members and a lowerportion.

terminating in spaced relation to the lower edge of said body membersforming an opening for a restricted flow of combustion gasestherethrough when said valve plates are in a closed position uponthepressure of combustion gases being insufiicient to open said valveplates.

5. In a fire tube boiler having a vertical row of hori zontally disposedfire tubes, said fire tubes each having an inlet and an outlet, acombustion chamber communicating with said inlets of saidfire tubes, aplurality of pressure operated valve means mounted on said outlets ofsaid fire tubes, said pressure operated valve means requiringdecrea'singly less pressure from the upper to the lower fire tubes toopen said valve means, and openings in said valve means permitting arestricted flow of combustion gases from said combustion chambers topass through said fire tubes when there is suificient pressure exertedby said combustion gases to open said valve means and said valve meansare in a closed position. 7

6. In a fire tube boilerhaving horizontally disposed fire tubes, saidfire tubes each having an inlet and an outlet, a plurality of tire tubeheat flow regulators each comprisin a cylindrical body member havingsubstantially the same" diameter as said fire tubes, removable meanssecuring said body members to said :outlets of said fire tubes, aplurality of valve plates, pivot means mounted on an upper portion ofeach 'of said ,valve plates and said body'memb ers' pivotally mountingeach,

of said valve plates to said body members and normally retaining saidvalve plates in a closed position, 'said'valve plates swinging to anopen position upon sufiicient pressure'being exerted by combustion gasesflowing through said fire tubes and each having a lower portionterminatare in a closed position upon the pressure of combustion gasesbeing insuflicient to open said valves plates, and said valve plates ofsaid upper fire tubes requiring a greater force to swing to an openposition than said valve plates of said lower fire tubes.

7. In a fire tube boiler having a plurality of horizontally disposedfire tubes mounted in a vertical tier, said fire tubes each having aninlet and an outlet, a plurality of fire tube heat flow regulators eachcomprising a cylindrical body member having substantially the samediameter as said fire tubes, a plurality of prongs secured to the innersurface of said cylindrical body member and extending outwardly of saidcylindrical body member, said prongs being slidably received by saidoutlets of said fire tubes for removably securing said body members tosaid fire tubes, a plurality of valve plates, pivot means mounted on anupper portion of each of said valve plates and said body memberspivotally mounting each of said valve plates to said body members andnormally retaining said valve plates in a closed position, said valveplates swinging to an open position upon suflicient pressure beingexerted by combustion gases flowing through said fire tubes and saidvalve plates having an upper portion engaging said body members and alower portion terminating in spaced relation to the lower edge of saidbody members forming an opening for the passage of combustion gasestherethrough when said valve plates are in a closed position, said valveplates of said upper fire tubes being lighter in weight than said valveplates of said lower fire tubes whereby a greater pressure of combustiongases are required to open the upper valve plates than the lower valveplates.

References Cited in the file of this patent UNITED STATES PATENTS538,589 Kemble Apr. 30, 1895 781,483 Wolf Jan. 31, 1905 895,926 WickhamAug. 11, 1908 973,022 Fitzpatrick Oct. 18, 1910 1,186,573 Haeusser June13, 1916 2,048,088 Wagner July 21, 1936 2,557,210 Viola et al June 19,1951 2,628,868 Mitc'nam Feb. 17, 1953 2,990,161 Blaskowski June 27, 1961FOREIGN PATENTS 388,121 Great Britain Feb. 23, 1933

1. IN A FIRE TUBE BOILER HAVING A PLURALITY OF FIRE TUBES, EACH OF SAIDFIRE TUBES HAVING AN INLET AND AN OUTLET, A FIRE TUBE HEAT FLOWREGULATOR COMPRISING A BODY MEMBER MEANS SECURING SAID BODY MEMBER TOSAID OUTLET OF SAID FIRE TUBE, A VALVE PLATE, PIVOT MEANS YIELDINGLYMOUNTING SAID VALVE PLATE ON SAID BODY MEMBER IN A NORMALLY CLOSEDPOSITION, SAID VALVE PLATE SWINGING IN A DIRECTION AWAY FROM SAID FIRETUBE TO AN OPEN POSITION UPON SUFFICIENT PRESSURE BEING EXERTED BYCOMBUSTION GASES AND BEING SMALLER THAN SAID FIRE TUBE WHEREBY ANOPENING IS FORMED WITH SAID VALVE PLATE IN SAID CLOSED POSITION TOPERMIT A RESTRICTED FLOW OF COMBUSTION GASES THROUGH SAID FIRE TUBE.